Ohio Rev. Code § 503.061
A board of township trustees, irrespective of the population or any other characteristic of the township, may adopt and submit to the director of transportation a resolution requesting the department of transportation to erect signs in the rights-of-way of state highways, other than freeways and expressways, located within that township and outside the limits of an incorporated municipality, indicating the boundaries of that township. Upon receipt of the resolution, the director shall agree to erect the signs for the township.
All signs erected under this section shall conform to the provisions contained in the manual adopted by the department of transportation pursuant to section 4511.09 of the Revised Code regarding the size, coloring, contents, lettering, and installation locations of the signs.
R.C. § 503.061